A conventional bicycle roller system is a training device for bicyclists typically consisting of three parallel cylindrical rollers supported horizontally in a frame. One roller is positioned below the front wheel of the bicycle and two are positioned below the driven rear wheel. The two rear rollers are placed such that the rear wheel is cradled between them and in contact with both rear rollers at once. The front roller is linked to one of the middle or rear roller, such as with a belt drive, so that when a bicycle is ridden upon the system, the rotation of the middle or rear roller causes the front roller to rotate, thereby resulting in both wheels of the bicycle spinning at the same speed and imparting stability to the bicycle via gyroscopic inertia. Such a bicycle roller system is described in U.S. Pat. No. 581,835 to Sturgis. This inertia allows the bicycle to be maintained in an upright position, but does little to limit lateral movement on the roller system. Minimal deviation of the front wheel from a straight-ahead orientation or a slight shift of the bicycle rider's weight, causes relatively large lateral movement of the bicycle as compared to a bicycle on the ground. This potential for lateral movement and its sensitivity to rider input make rollers an excellent training device to improve bicycle handling skills, but severely limit their use for cardiovascular fitness. The novice and even average rider is constantly at risk of riding off the side of the rollers, as is an accomplished bicyclist should he become fatigued and lose concentration while riding. One solution to the problem of riding off the sides of the rollers is described in U.S. Pat. No. 463,862 to Guignard which employs concave rollers as a means for centering the bicycle. Concave rollers in which the concavity is minimal (i.e., rollers having a shallow curvature), however, offer little aid in keeping the bicycle centered upon the roller. Concave rollers in which the concavity is severe (i.e., rollers having a deep curvature) reduce the skill-training benefit of rollers, while giving the sensation of riding down into a groove in the ground. One effort to combat this sensation was to utilize sloped edges on a normal cylindrical roller as described in U.S. Pat. No. 6,500,098 to Werner. The sloped edges of the rollers however have a tendency to buck or startle a user, causing them to swerve or still ride off of the roller. Because of the above difficulties, bicycle roller use is usually limited to skill training by experienced and accomplished riders.
In addition, the use of a crowned roller on a rear roller of a bicycle roller trainer is also known in the art, as shown in U.S. Patent Publ. No. 2006/0217237 (Paragraph [0046]), which discloses a bicycle roller trainer having flat middle and front rollers, and optionally a convex rear roller. Such crowned rear rollers, however, result in an uncomfortable and destabilizing phenomenon in which movement of a bicycle to the smaller diameter side sections causes the bicycle to move backward, which causes an uncomfortable sensation to the user of backward motion, further potentially disrupting the user's balance on the roller trainer.
Accordingly, there is a need to develop bicycle roller trainers that improves stability, especially for first time and novice users who have not developed the skill of balancing on the roller trainer.